Duplicate of other run-length encoding kata, like for example this one: https://www.codewars.com/kata/546dba39fa8da224e8000467

• Your random tests are not doing what you promised us in the description.
• This has been done. Please think up something more original.

Duplicate of https://www.codewars.com/kata/merge-two-arrays

Combining two API methods and nothing more does not really make for a very interesting kata.

Your random tests are unreliable. If r() generates the same number as it did before, you're expecting false when true would be correct.

You're not running into this, mostly, because you have way too few random tests. Besides, they're not random. The expected value is predictable.